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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Subwoofer Forum => Topic started by: Ivan Beaver on December 12, 2013, 07:47:04 PM
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This topic comes up a fair bit-and I have never seen any data one way or the other.
So I decided to take some before and after measurements.
Attached is a shot. The purple is before and green is after.
Yes there is a difference-but it is pretty small. Is it enough to be concerned with or audible?
I will let you decide.
I tried hard to make sure that nothing changed between measurements.
The break in procedure was 20Hz with 30V input for 3 hours. Would longer make any more difference-I am not sure-but this was all the time I had for the test.
Just thought I would share this little test.
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The break in procedure was 20Hz with 30V input for 3 hours.
Ivan,
I expected 'more' after burn-in … I suspect the coil was still warm(er) when you took the 'after' measurement ?
Both measurements are equal at frequency, where impedance is high, I guess port must kick in there somewhere ??
Thank you for sharing. I'm a bit ashamed I never did this myself.
Respectfully
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I have been told the speaker suspension becomes more flexible after break-in, and that the speaker outputs less but goes deeper. Looking at Ivan's measurement curves, the difference appears anecdotic to me.
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Ivan,
I expected 'more' after burn-in … I suspect the coil was still warm(er) when you took the 'after' measurement ?
Both measurements are equal at frequency, where impedance is high, I guess port must kick in there somewhere ??
Thank you for sharing. I'm a bit ashamed I never did this myself.
Respectfully
This was in a short tapped horn.
The "new" transfer measurement was made with around a 3V input. Then I used a separate generator to drive the 20Hz tone (so I would not do any adjustment to the measurement/generator system), then switched the input to the amp back to the 3V (or so) measurement generator.
I did let it cool down maybe 30 minutes before retesting.
I am not saying this is an absolute test-and yes the break in period could have been a lot longer-and I should have let it cool down overnight-to be exact.
But I had a rare little period of time to do some "playing" and just wanted to share what I found and the parameters of the test.
Other test could be different.
This was done inside the warehouse-with the mic about 1M from the cabinet in a ground plane configuration.
I don't think any objects were moved around that would affect the reflections-but there might have been.
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Thanks for posting this, Ivan. I've long thought that "break-in" was a criminal act, not a loudspeaker thing. Your measurements appear to confirm this.
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Dick Pierce an audio consultant wrote this way back in 1996:
>My question is two fold: why would speakers need breaking in ? Is
>anyone aware of any measurements and tests having being done of before
>and after performance that has shown a measurable difference?
I am aware of at least one person who has done extensive measurements
of this type: me. I have a database of several thousand drivers that I
have measured.
>I have been able to think of only one mechanism attributable to the
>speaker that to me could conceivably be at play if there is indeed an
>effect. It is that the elastomeric materials that form the suspension
>of the cone of a driver are somewhat stiff to start with and become
>more pliant through use, thereby allowing the cones of the drivers to
>move more freely with use.
>I don't believe this though, as an elastomeric material that exhibited
>such a change in properties would surely continue to 'loosen' over
>time so as to go beyond the point of aurally optimum elasticity so
>that there was an eventual degradation in sound quality such as when
>the voice coil made some unwanted high speed excursions into
>stationary bits.
Well, there are, indeed, several mechanism that are, indeed, at work
that cause the operating parameters of drivers to change through use.
However, the notion that once one gets a speaker home it requires
"breaking in" suffers from several problems.
First, as a driver comes off the line, it's actual performance if
fairly far from it's intended performance target. Reasons for this
include the fact that the centering spider, typically manufactured
from a varnish- impregnated linen, is far stiffer than needed. Working
the driver back and forth lossens the spider considerably.
Now, one might say: there's objective proof of the need to "break in"
a loudspeaker! Not so fast. The break-in period for the spider is on
the order of several seconds, and if it takes you several seconds or
minutes or whatever once you get the speakers home to loosen the
centering spdier, it's not proof of the need to break thme in, it's
proof that the speaker you just bought HAS NEVER BEEN TESTED!
But, on to other points.
When I measure a driver, I can see a significant change in a variety
of operating parameters as the speaker is driven. Usually, in woofer,
the resonant frequency drops as the speaker is used, often by as much
as 10-20%. This is due, as you suggest, to a relaxing of the
elastomers used in the suspension.
However. If I turn the stimulus off, within a few minutes most, if not
all, of the change has completely recovered, and we're back to go
again. The elastomer has recovered from it's stresses (this is
especially true of certain polybutadene-styrene surround
formulations).
There are plenty of other, real, physical changes. For example, one
can see a reduction of the electrical Q with time under heavy use,
simply because of the positive temperature coefficient of the
resistance of the voice coil. Allow the speaker to cool down, and it's
completely recoverable.
Get it hot enough, and you might permanently loose some flux density
in the magnet. But you have to get REAL hot to do that. Hotter than
most of the compounds used in making a speaker can endure without
catastrophic failure (damned few glues, varnishes, cones and
insulating materials can withstand the temperatures neede to reach the
Curie points of the typical magnetic materials found in loudspeakers).
>What I really think is at play in all this is the adaptive signal
>processing abilities of the brain. It is not the speakers which get
>broken in, rather it is ones 'ears'.
When this has been suggested, despite the fact there's about a century
of research backing it, it is more often than not greeted with jeers
and cries. See, you can't sell special "break-in" CD's if the speakers
aren't broken in.
>I would be interested to hear other opinions on this.
Well, there will be loads of opinions. However, actual data on several
thousand drivers don't seem to give two shits about opinions, the
usual claims of "mysterious unmeasurable quantities" notwithstanding.
--
| Dick Pierce |
| Loudspeaker and Software Consulting |
11/2/1996
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Thanks for posting this, Ivan. I've long thought that "break-in" was a criminal act, not a loudspeaker thing. Your measurements appear to confirm this.
I have long thought that that transducer break in was in the subjects ears and or perception.
I found this 2005 article of interest. http://www.audioholics.com/loudspeaker-design/speaker-break-in-fact-or-fiction
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I know guitar speakers sound slightly harsh and hashy sounding till you beat um up a little.I know guys go as far as spraying the cones with fabric softener and running a 60cycle hum from a variac through um for hours and some remove the outter doping from the surround.Warren Haynes I guess blasts music trough his Marshall cabs for something like 24hrs to break um in.
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I know guitar speakers sound slightly harsh and hashy sounding till you beat um up a little.I know guys go as far as spraying the cones with fabric softener and running a 60cycle hum from a variac through um for hours and some remove the outter doping from the surround.Warren Haynes I guess blasts music trough his Marshall cabs for something like 24hrs to break um in.
Except now you've gone into the deep end of speaker superstition pool...yes, it may change the sound running the driver through the wash, but it's really-really-really a subjective area.
Also, any comparisons made involving a cold or hot voice coil are not part of the equation, that's a different phenomena unrelated to possible "break in" issues with a driver.
Best regards,
John
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Except now you've gone into the deep end of speaker superstition pool...yes, it may change the sound running the driver through the wash, but it's really-really-really a subjective area.
Also, any comparisons made involving a cold or hot voice coil are not part of the equation, that's a different phenomena unrelated to possible "break in" issues with a driver.
Best regards,
John
The only thing "breaking in" is the truth. And the truth is that for professional audio loudspeakers, "break in" is voodoo bullshit, par excellence.
Break-in? Plug them in and use them. There, you're done.
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Warren Haynes I guess blasts music trough his Marshall cabs for something like 24hrs to break um in.
Why do you guess this?
Steve.
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The only thing "breaking in" is the truth. And the truth is that for professional audio loudspeakers, "break in" is voodoo bullshit, par excellence.
Break-in? Plug them in and use them. There, you're done.
And think of it this way. Let's say you buy a brand new PA system.
Do you take it to the gig and Instantly perform critical listening or sound checks?
NO-in most every case I can think of, at least some canned music is played for a little bit before attempting to do sound check. You know check for coverage maybe max level etc.
That should be enough to "break it in" as if the subtle differences/changes would even be noticed.
I do know there are some manufacturers who make a big deal of going ahead and "breaking in" the speakers so that they are "ready to play" when you get them.
Now it is not a bad idea to run them for awhile to make sure they work fine-but to me it seems as if it is just another thing to "baffle" the user who does not know better and make them "think" they are getting something that they are not.
And unless my test (i did just one) was flawed-how would you know if the speakers were broken in or not? It is not as if there was enough change to make any noticeable difference
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Why do you guess this?
Steve.
Well its what I've read on forums on more than one occasion but being a few years ago wanted to give a blanket answer incase I screwed up a detail or two. ;)
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Well its what I've read on forums on more than one occasion but being a few years ago wanted to give a blanket answer incase I screwed up a detail or two. ;)
Just because somebody does something (especially in audio) does not mean that it NEEDS to be done or actually makes a difference.
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True,
But in a way guitarist are going for differant purposes than pa systems. Gotta figure Warren Haynes is a Marshall plexi guy. And allot of them old school guitar sounds involve high volume cone breakup.So softening the cone may give a differance in that respect.
I dunno I don't push my amps THAT hard and try not to blow up my vintage greenbacks,which are 40+ yrs broken in.
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I just recently completed a re-cone on a powered speaker I own. I compared it to the other ( same model ) one I had which still had original components. I could not hear and or discern any audible difference between the two. The comparison was done with a speaker with 6 year old components and the first fire up of the re-coned unit. I have never really believed that a break in would make a difference. The electrical and surrounding box aspects of the speaker are unchanging. The only change in a speaker might be the loosening up of the surround and spider material? I don't see the minor difference to be enough to make a major tone difference. Now if the speaker originally had a doped surround and the re-cone was not doped, then perhaps a difference could be heard?
As for guitar speakers and break in.........?????????? I think if there wasn't such a BS circus about them, we would all be better off. Guitar speakers are grossly overpriced for what they are and the fact that about 90% of them are trying to capture a sound that already exists is even worse. To me it's silly to make a speaker to sound like an already existing speaker and drive the price up even more. The disparity in price from the stockers to the sought after models is silly. It's roughly the same cost to produce a Vintage 30 as a low end seventy 80. Yet the V-30's will set you back about double the cost. Don't even get me started on the Blue model that will set you back close to $300 for a 15watt speaker!!!!! The speaker manufacturers will sell an Eskimo ice if they could. They are for the most part thriving off of a silly legacy driven platform as it is. To make matters worse, we place these speakers in untuned and abhorrent box designs that were basically more about the utilization of one piece of plywood. The 4X12 cabinets are beamy and some are so bad that cancellation will occur in places around the speaker where you may be standing! The market is made up in such a way that by the time you acquire the things you want, you can't afford to change your mind about it.
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The only thing "breaking in" is the truth. And the truth is that for professional audio loudspeakers, "break in" is voodoo bullshit, par excellence.
Break-in? Plug them in and use them. There, you're done.
Sorry, I wasn't clear in my response. "Break in" is a myth, no denying that.
John
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True,
But in a way guitarist are going for differant purposes than pa systems. Gotta figure Warren Haynes is a Marshall plexi guy. And allot of them old school guitar sounds involve high volume cone breakup.So softening the cone may give a differance in that respect.
I dunno I don't push my amps THAT hard and try not to blow up my vintage greenbacks,which are 40+ yrs broken in.
f
So why is he "breaking them in"?
If the "old sound" is what he is after-then why buy new speakers-why not just use the old ones he has?
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Sorry, I wasn't clear in my response. "Break in" is a myth, no denying that.
John
John, NP. My reply was for support, not contradiction.
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John, NP. My reply was for support, not contradiction.
Thanks. I still could have been more clear.
Best regards,
John
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I believe in speaker break in...
They broke the window on my car a stole the sub woofer!
Ivan...back to work now on that new "OS100" speaker ;D
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I believe in speaker break in...
They broke the window on my car a stole the sub woofer!
Ivan...back to work now on that new "OS100" speaker ;D
It is getting close. Along with some other "members of the family" in the works.
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f
So why is he "breaking them in"?
If the "old sound" is what he is after-then why buy new speakers-why not just use the old ones he has?
Allot those plexi guys and vintage amp hounds don't want to beat the crap outta there old speakers on the road and save the vintage cabs for studio.Original pulsonic coned greenback Celestions sound waaaayyy warmer than the Reissue greenbacks for instance.So rather than risk blowing up an expensive vintage speaker that cannot be replaced,they do weird voodoo rituals to try and make some readily available speakers sound the way they want.
Like I said guitar is a whole differant world really.look at the amount of time invested in building distortion units,the main thing that is avoided in pro audio.
With guitar there is more than just sound involved there is feel of the amplified instrument and that comes from the sum of the whole rig from guitar-pedals-amp-tubes-transformers-speakers-cabs and how they react.
Not trying to be a ball breaker I know you know speaker design more than I ever will.I'm just sayin guitar players have a focused zoomed in idea of what they want there guitar to sound like in there head and if the "real thing" is impractical you do what you can to modify what you can get,to sound like it.
Ask any crazy that spends $1200+ for a quad of Genalex KT88s ;)
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Allot those plexi guys and vintage amp hounds don't want to beat the crap outta there old speakers on the road and save the vintage cabs for studio.Original pulsonic coned greenback Celestions sound waaaayyy warmer than the Reissue greenbacks for instance.So rather than risk blowing up an expensive vintage speaker that cannot be replaced,they do weird voodoo rituals to try and make some readily available speakers sound the way they want.
Like I said guitar is a whole differant world really.look at the amount of time invested in building distortion units,the main thing that is avoided in pro audio.
With guitar there is more than just sound involved there is feel of the amplified instrument and that comes from the sum of the whole rig from guitar-pedals-amp-tubes-transformers-speakers-cabs and how they react.
Not trying to be a ball breaker I know you know speaker design more than I ever will.I'm just sayin guitar players have a focused zoomed in idea of what they want there guitar to sound like in there head and if the "real thing" is impractical you do what you can to modify what you can get,to sound like it.
Ask any crazy that spends $1200+ for a quad of Genalex KT88s ;)
And then go talk to a "hi-fi" guy about what they "think" they are doing with various "tweaks".
Just as proof that they are not hearing what they "think" they are-consider this.
I have worked with lots of touring musicians over the years. MANY times they will ask for me to change something in their monitor-AND BEFORE I can get my hand to the tone or volume control they say "That's good".
SO WHAT CHANGED? Me putting my hand near the knob? i don't think so-i can't hold it there the whole show---------------
Or the fact that THEY THINK something happened. The mind/ear is real easy to fool when it comes to audio.
Just do this for yourself. Play a track through a channel on a console. Now hit the mute button on and off and listen real hard for how the sound "changes". Often you will swear that something has changed.
So what do you do now? How do you make the switch have that particular "sound".
I'm just saying that just becasue somebody DOES SOMETHING does NOT mean that anything really happened.
But if you believe it did-then I guess it did.
So we have people that are being fooled by nothing and they are spreading that "foolishness".
Yes some things make a difference-others don't. You need FACT to separate the two.
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And then go talk to a "hi-fi" guy about what they "think" they are doing with various "tweaks".
Just as proof that they are not hearing what they "think" they are-consider this.
I have worked with lots of touring musicians over the years. MANY times they will ask for me to change something in their monitor-AND BEFORE I can get my hand to the tone or volume control they say "That's good".
SO WHAT CHANGED? Me putting my hand near the knob? i don't think so-i can't hold it there the whole show---------------
Or the fact that THEY THINK something happened. The mind/ear is real easy to fool when it comes to audio.
Just do this for yourself. Play a track through a channel on a console. Now hit the mute button on and off and listen real hard for how the sound "changes". Often you will swear that something has changed.
So what do you do now? How do you make the switch have that particular "sound".
I'm just saying that just becasue somebody DOES SOMETHING does NOT mean that anything really happened.
But if you believe it did-then I guess it did.
So we have people that are being fooled by nothing and they are spreading that "foolishness".
Yes some things make a difference-others don't. You need FACT to separate the two.
You have pointed out a very interesting "effect". I too have had the "I didn't touch anything now it's fine" situation.
The power of your mind to affect perception cannot be discounted and one only has to look at visual perception "tricks" as an indicator.
The last line in your post sums it up!
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You have pointed out a very interesting "effect". I too have had the "I didn't touch anything now it's fine" situation.
The power of your mind to affect perception cannot be discounted and one only has to look at visual perception "tricks" as an indicator.
The last line in your post sums it up!
I've seen this, too, and sometimes it's the psychology... and sometimes it's physics... the request for say, more vocal happens right as the guitarist stops playing and suddenly "hey, that's perfect!"
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...The market is made up in such a way that by the time you acquire the things you want, you can't afford to change your mind about it.
That should be the "Quote of The Day!".
-Dennis
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Truth ^^^^^^^^^^^^^^^^^^^^^ :o :o :o :o :o :o
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Break in is a fabulous concept from a vendor's point of view. They would be mad to break in any products they sold.
You buy a product and take it home. Don't like the sound? Just wait for it to break in. :-) It will sound much better. Trust us, you will notice a huge difference. :-)
I had heard a plausible mechanism for headphone break in: over time the cushioning foam compacts and the resonant space between the driver and the eardrum shrinks.
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Break in is a fabulous concept from a vendor's point of view. They would be mad to break in any products they sold.
You buy a product and take it home. Don't like the sound? Just wait for it to break in. :-) It will sound much better. Trust us, you will notice a huge difference. :-)
I had heard a plausible mechanism for headphone break in: over time the cushioning foam compacts and the resonant space between the driver and the eardrum shrinks.
But there are some manufacturers who market the fact that their drivers are "pre broken in"-so you don't have to. You get to pay extra for that.